Sounds like a standard holiday, visiting all the repair shops on the way.
You had more overheat problems after you cleaned the rad?
If you only use garden hose pressure, or less? (
my pressure is about 40# here) and use degreaser and be carefull, you should not bend the fines on the rad. I have had no real problems. (temp ran up on a trip in 2009 in 39*C = 102F on the long East pull out of Osoyoos, BC.
49.009582,-119.411007 - Google Maps
I just geared down to keep the RPM at 2000, shut down the AC, and kept moving.
I have, since that time, installed a two-way vent on each side to assist in air movement over the batteries/exhaust area, and the AC Condensor/engine area.
Dave